The present invention relates to a substrate processing apparatus and method for performing, for example, substrate processing such as developing processing and the like for a substrate.
A mask for forming a predetermined pattern on a front face of a semiconductor wafer (hereinafter, referred to as "wafer") or a glass substrate (LCD substrate) of a liquid crystal display is obtained by applying a resist to the front face of a wafer or the like and then radiating rays of light, electron rays, ion beams, or the like to the resist surface, and performing developing.
The developing processing here is performed by dissolving portions irradiated with light or the like or portions without such irradiation in an exposure process with use of an alkaline water solution or the like, and conventionally it has been performed as follows. The technique is that, as shown in FIG. 11A, a substrate, for example, a wafer W is first suction-held, for example, on a spin chuck 10 having a vacuum suction function, and a supply nozzle 11 in a rod shape having many discharge holes is placed above the center of the wafer W. Then, as shown in FIG. 11B, the wafer W is rotated 180 degrees while a developing solution D is supplied to the wafer surface from the supply nozzle 11 to thereby perform heaping of the developing solution D on the resist film. Subsequently, as shown in FIG. 11C, the wafer W is left untouched for 60 seconds with the rotation of the wafer W being stopped, and thereafter a rinse liquid is supplied onto the wafer surface to wash away the developing solution.
However, for example, in the case of using an I-line resist, developing unevenness occurs in the above-described developing method, whereby developed line width varies depending on position, which causes a disadvantage, for example, a difference in line width of about 4 nm between an area close to the center of the wafer and a rim portion thereof. From a study of a cause of the above, it is conceivable that degrees of proceeding of the developing depend on the temperature of the developing solution D, and therefore temperature distribution occurs in the developing solution D within the plane of the wafer. In other words, the developing solution D is controlled to a temperature of, for example, about 23.degree. C., but water contained in the developing solution D evaporates while the wafer W is subjected to the solution heaping and then left untouched, whereby latent heat in the developing solution D is lost, and thus the temperature of the developing solution D decreases with time as shown in FIG. 12.
On the other hand, the spin chuck 10 for holding an area close to the center of the wafer has a certain size to perform ascent and descent and rotation while holding the wafer W. Moreover, the spin chuck 10 is maintained at a temperature of, for example, about 23.degree. C. by, for example, a temperature controlled water so that a thermal influence from a motor (not shown) for driving the spin chuck 10 is eliminated. Accordingly, it is conceivable that the spin chuck 10 has a large heat capacity, and degrees of temperature decrease of the developing solution D is different between a portion of the wafer W in contact with the spin chuck 10 and a portion not in contact therewith, and thus the temperature of the area close to the center of the wafer is hard to decrease compared with the rim portion thereof.
Therefore, it is presumed that temperature difference in the developing solution D of about 1.degree. C. occurs between the area close to the center of the wafer and the rim portion thereof at the start of a rinse, whereby there occurs unevenness in the developing state, resulting in variations in finished measurements.